The name probably means "oi" (forest) and "ard" (person),[2] and they were counted among the "forest people" in the 13th century[citation needed]. A second opinion believes the name derives from Mongolian word "oirt" (or "oirkhon") meaning "close (as in distance)," as in "close/nearer ones."

The name Oirat may derive from a corruption of the group's original name Dörben Öörd, meaning "The Allied Four." Perhaps inspired by the designation Dörben Öörd, other Mongols at times used the term "Döchin Mongols" for themselves ("Döchin" meaning forty), but there was rarely as great a degree of unity among larger numbers of tribes as among the Oirats.

The Todo Bichig writing system remained in use in Kalmykia (Russia) until the mid-1920s when it was replaced by a Latin-based script, and later the Cyrillic alphabet. It can be seen in some public signs in the Kalmyk capital, Elista, and is superficially taught in schools. In Mongolia it was likewise replaced by the Cyrillic alphabet in 1941. Some Oirats in China still use Todo Bichig as their primary writing system, as well as Mongolian script.

A monument of Zaya Pandita was unveiled on the 400th anniversary of Zaya Pandita's birth, and on 350th anniversary of his creation of the Tod Bichig.[5]

The Oirats share some history, geography, culture and language with the Eastern Mongols, and were at various times united under the same leader as a larger Mongol entity — whether that ruler was of Oirat descent or of Chingissids.

Comprising the Khoshut (Mongolian: "хошууд", hošuud), Choros or Ölöt ("өөлд", Ööld), Torghut ("торгууд", Torguud), and Dörbet ("дөрвөд", Dörvöd) ethnic groups, they were dubbed Kalmyk or Kalmak, which means "remnant" or "to remain", by their western Turkic neighbours. Various sources also list the Bargut, Buzava, Keraites, and Naiman tribes as comprising part of the Dörben Öörd; some tribes may have joined the original four only in later years. This name may however reflect the Kalmyks' remainingBuddhist rather than converting to Islam; or the Kalmyks' remaining in then Altay region when the Turkic tribes migrated further west.

After the fall of the Yuan dynasty, Oirat and Eastern Mongols had developed separate identities to the point where Oirats called themselves "Four Oirats" while they only called those under the Khagans in the east as "Mongols".[6]

One of the earliest mentions of the Oirat people in a historical text can be found in The Secret History of the Mongols, the 13th century chronicle of Genghis Khan's rise to power. In the Secret History, the Oirats are counted among the "forest people" and are said to live under the rule of a shaman-chief known as bäki. They lived in Tuva and Mongolian Khövsgöl Province and the Oirats moved to the south in the 14th century.[7]

In one famous passage the Oirat chief, Quduqa Bäki, uses a yada or 'thunder stone' to unleash a powerful storm on Genghis' army. The magical ploy backfires however, when an unexpected wind blows the storm back at Quduqa. During early stages of Temujin Genghis's rise, Oirats under Quduqa bekhi fought against Genghis and were defeated. Oirats were fully submitted to Mongol rule after their ally Jamukha, Temujin's childhood friend and later rival, was destroyed. Subject to the khan Oirats would form themselves as a loyal and formidable faction of the Mongol war machine. In 1207, Jochi the eldest son of Genghis, subjugated the forest tribes including the Oirats and the Kyrgyzs. The Great Khan gave those people to his son, Jochi, and had one of his daughters, Checheygen, married the Oirat chief Khutug-bekhi or his son. There were notable Oirats in the Mongol Empire such as Arghun Agha and his son Nowruz. In 1256, a body of the Oirats under Bukha-Temür (Mongolian: Буха-Төмөр, Бөхтөмөр) joined Hulagu's expedition to Iran and fought against Hashshashins, Abbasids in Persia. The Ilkhan Hulagu and his successor Abagha resettled them in Turkey. And they took part in the Second Battle of Homs where the Mongols were defeated.[8] The majority of the Oirats, who were left behind, supported Ariq Böke against Kublai in the Toluid Civil War. Kublai defeated his younger brother and they entered the service of the victor. In 1295, more than 10,000 Oirats under Targhai Khurgen (son-in-law of the Borjigin family) fled Syria, then under the Mamluks because they were despised by both Muslim Mongols and local Turks. They were well received by the EgyptianSultanAl-Adil Kitbugha of Oirat origin.[9] Ali Pasha, who was the governor of Baghdad, head of an Oirat ruling family, killed Ilkhan Arpa Keun, resulting in the disintegration of Mongol Persia. Due to the fact that the Oirats were near both the Chagatai Khanate and the Golden Horde, they had strong ties with them and many Mongol khans had Oirat wives.

After the expulsion of the Yuan dynasty from China, the Oirats revived in history as a loose alliance of the four major West Mongolian tribes (Dörben Oirad). The alliance grew, taking power in the remote region of the Altai Mountains, northwest of Hami oasis. Gradually they spread eastward, annexing territories then under the control of the Eastern Mongols, and hoping to reestablish a unified nomadic rule under their banner.

A non-Genghisids alliance was formed by the Four Oirats, made out of the Keraites, Naiman, Barghud, and old Oirats.[10][11]

The only Borjigid ruling tribe was the Khoshuts, while the others were ruled by non-Genghisids. The Ming Chinese had helped the Oirat's rise to power over the Mongols during the Ming Yongle Emperor's reign after 1410 when the Ming defeated the Qubilaid Öljei Temür and the Borjigid power was weakened.[12] The Borjigid Khans were displaced from power by the Oirats with Ming help and only ruled as puppet khans until the Ming and Oirats ended the alliance when the Yongle Emperor launched a campaign against them.[13]

The greatest ruler of the Four Oirats (Mongolian: "дөрвөн ойрд", "дөрвөн ойрaд") was Esen Tayisi who led the Four Oirats from 1438 to 1454, during which time he unified Mongolia (both Inner and Outer) under his puppet khan Toghtoa Bukha. In 1449 Esen Tayisi and Toghtoa Bukh mobilized their cavalry along the Chinese border and invaded Ming China, defeating and destroying the Ming defenses at the Great Wall and the reinforcements sent to intercept the cavalry. In the process, the Zhengtong Emperor was captured at Tumu. The following year, Esen returned the emperor after an unsuccessful ransom attempt. After claiming the title of khan, to which only lineal descendants of Genghis Khan could claim, Esen was killed. Shortly afterwards, Oirat power declined.

From the 14th until the middle of the 18th century, the Oirats were often at war with the Eastern Mongols and also few times reunited with the Eastern Mongols during the rule of Dayan Khan and Tümen Zasagt Khan.

The Qing Empire defeated Dzungars in the 1720s and proclaimed the rule over Oriats through Manchu-Mongols-Alliance (a series of systematic arranged-marriages between princes and princesses of Manchu with those of Khalkha Mongols and Oriats Mongols, which was set up as a royal policy carried out over 300 years), as well as over the Khoshut-controlled Tibet.

In 1723 Lobzang Danjin, another descendant of Güshi Khan, took control of Amdo and tried to assume Khoshut Khanate. He fought against Manchu-Qing Dynasty army, but was defeated only in the following year and 80,000 people from his tribe were executed by Manchu army due to his "rebellion attempt".[14] By that period, Upper Mongolian population reached 200,000 and were mainly under the ruling of Khalkha Mongols princes who were in marriage alliance with Manchu royal & noble families. Thus, Amdo fell under Manchu domination.

The Qing (or Manchu) conquered China in the mid-17th century and sought to protect its northern border by continuing the divide-and-rule policy their Ming predecessors had successfully instituted against the Mongols. The Manchu consolidated their rule over the East Mongols of Manchuria. They then persuaded the East Mongols of Inner Mongolia to submit themselves as vassals. Finally, the East Mongols of Outer Mongolia sought the protection of the Manchu against the Dzungars.

Some scholars estimate that about 80% of the Dzungar population were destroyed by a combination of warfare and disease during the Manchu-Qing conquest of Dzungaria in 1755-1757.[15] The Zunghar population reached 600,000 in 1755.

The main population of the Choros, Olot, Khoid, Baatud, Zakhchin Oirats who battled against the Qing were killed by the Manchu soldiers and after the fall of the Dzungar Khanate they became small ethnic groups. There were 600,000 Khalkha Mongols and 600,000 Oirats in 1755 and now 2,3 million Khalkha and 638,372 Oirats live in four counties while a few hundred Choros people live in Mongolia.

Kho Orlok, tayishi of the Torghuts, and Dalai Tayishi of Dorbets, led their people (200,000-250,000 people, mainly Torghuts) westward (Volga River) in 1607 and they established the Kalmyk Khanate. By some accounts this move was precipitated by internal divisions or by the Khoshut tribe; other historians believe it more likely the migrating clans were seeking pastureland for their herds, scarce in the Central Asian highlands. Part of the Khoshut and Ölöt tribes would join the migration almost a century later. The Kalmyk migration had reached as far as the steppes of southeast Europe by 1630. At the time, that area was inhabited by the Nogai Horde. But under pressure from Kalmyk warriors, the Nogais fled to the Crimea and the Kuban River. Many other nomadic peoples in the Eurasian steppes subsequently became vassals of the Kalmyk Khanate, part of which is in the area of present-day Kalmykia.[16]

The Kalmyks became Russian ally and a treaty to protect southern Russian borders was signed between the Kalmyk Khanate and Russia. Later they became nominal, then full subjects of the Russian Tsar. In 1724 the Kalmyks came under control of Russia. By the early 18th century, there were approximately 300-350,000 Kalmyks and 15,000,000 Russians.[17] The Tsardom of Russia gradually chipped away the autonomy of the Kalmyk Khanate. These policies encouraged establishment of Russian and German settlements on pastures where the Kalmyks used to roam and feed their livestock. The Russian Orthodox church, by contrast, pressured Buddhist Kalmyks to adopt Orthodoxy. In January 1771 the oppression of czarist administration forced a larger part of Kalmyks (33 thousands households or approximately 170 thousands individuals) to migrate to Dzungaria.[18] 200,000 (170,000)[19] Kalmyks began the migration from their pastures on the left bank of the Volga River to Dzungaria, through the territories of their Bashkir and Kazakh enemies. The last Kalmyk khan Ubashi led the migration to restore the Dzungar Khanate and Mongolian independence.[19] As C.D Barkman notes "It is quite clear that the Torghuts had not intended to surrender the Chinese, but had hoped to lead an independent existence in Dzungaria".[20] Ubashi Khan sent his 30,000 cavalries to the Russo-Turkish War in 1768-1769 to gain weapon before the migration. The Empress Catherine the Great ordered the Russian army, Bashkirs and Kazakhs to exterminate all migrants and Catherine the Great abolished the Kalmyk Khanate.[19][21][22] The Kyrgyzs attacked them near Balkhash Lake. About 100,000-150,000 Kalmyks who settled on the west bank of the Volga River couldn't cross the river because the river didn't freeze in the winter of 1771 and Catherine the Great executed influential nobles of them.[19] After seven months of travel, only one-third (66,073)[19] of the original group reached Dzungaria (Balkhash Lake, western border of the Manchu-Qing Empire).[23] The Manchu-Qing Empire transmigrated the Kalmyks to five different areas to prevent their revolt and influential leaders of the Kalmyks died soon (killed by the Manchus). Following the Russian revolution their settlement was accelerated, Buddhism stamped out and herds collectivised.

On January 22, 1922, Mongolia proposed to immigrate the Kalmyks during a famine in Kalmykia but the Russian government refused. Some 71-72,000 (93,000?; around half of the population) Kalmyks died during that famine.[24] The Kalmyks revolted against Russia in 1926, 1930 and 1942-1943. In March 1927, Soviet deported 20,000 Kalmyks to Siberia, tundra and Karelia.[24] The Kalmyks founded sovereign Republic of Oirat-Kalmyk on March 22, 1930. The Oirat's state had a small army and 200 Kalmyk soldiers defeated 1,700 Soviet soldiers in Durvud province of Kalmykia but the Oirat's state destroyed by the Soviet Army in 1930. Kalmykian nationalists and Pan-Mongolists attempted to migrate Kalmyks to Mongolia in the 1920s. Mongolian government suggested to accept the Mongols of Soviet Union, including Kalmyks, to Mongolia but Russia refused the attempt. [24]

In 1943, the entire population of 120,000 Kalmyks were deported to Siberia by Stalin, accused of supporting invading Axis armies attacking Stalingrad (Volgograd); a fifth of the population is thought to have perished during and immediately after the deportation. [25][26][27] Around half of (97-98,000) Kalmyk people deported to Siberia died before being allowed to return home in 1957.[28] The government of the Soviet Union forbade teaching Kalmyk language during the deportation.[29][30][31] The Kalmyks' main purpose was to migrate to Mongolia. Mongolian leader Khorloogiin Choibalsan attempted to migrate the deportees to Mongolia and he met with them in Siberia during his visit to Russia. Under the Law of the Russian Federation of April 26, 1991 "On Rehabilitation of Exiled Peoples" repressions against Kalmyks and other peoples were qualified as an act of genocide. Now they are trying to revive their language and religion. In 2010 Kalmyks were 176,800 people.

The Mongols of Xinjiang form a minority, principally in the northern part of the region, numbering 194,500 in 2010, about 50,000 of which are Dongxiangs.[32] They are primarily descendants of the surviving Torghuts and Khoshuts who returned from Kalmykia, and of the Chakhar stationed there as garrison soldiers in the 18th century. The emperor had sent messages asking the Kalmyks to return, and erected a smaller copy of the Potala in Jehol (Chengde), (the country residence of the Manchu Emperors) to mark their arrival. A model copy of that "Little Potala" was made in China for the Swedish explorer Sven Hedin, and was erected at the World's Columbian Exposition of Chicago (1893). It is now in storage in Sweden, where there are plans to re-erect it. Some of the returnees did not come that far and still live, now as Muslims, at the South-western end of Lake Issyk-kul in present-day Kirghizia.

Bordering Gansu and west of Irgay River[where?] is called Alxa or Alaša, Alshaa and Mongols who moved there are called the Alasha Mongols.

Törbaih Güshi Khan's 4th son Ayush was opposed to the Khan's brother Baibagas. Ayush's eldest son is Batur Erkh Jonon Khoroli. After the battle between Galdan Boshigt Khan and Ochirtu Sechen Khan, Batur Erkh Jonon Khoroli moved to Tsaidam with his 10,000 households. The 5th Dalai Lama wanted land for them from the Qing government, thus in 1686, the Emperor permitted them to reside in Alasha.

In 1697, Alasha Mongols were administered in 'khoshuu' and 'sum' units. A khoshuu with eight sums was created, Batur Erkh Jonon Khoroli was appointed to Beil (prince), and Alasha was thus a 'zasag-khoshuu'. Alasha was however like an 'aimag' and never administered under a 'chuulgan'.

In 1707, when Batur Erkh Jonon Khoroli died, his son Abuu succeeded him. He was in Beijing from his youth, served as bodyguard of the Emperor, and a princess (of the Emperor) was given to him, thus making him a 'Khoshoi Tavnan', i.e. Emperor's groom. In 1793, Abuu became Jün Wang. There are several thousand Muslim Alasha Mongols.[33]

Mongols who lived along the Ejin River (Ruo Shui) descended from Ravjir, a grandson of Torghut Ayuka Khan from the Volga River.

In 1678, Ravjir - with his mother, younger sister and 500 people - went to Tibet to pray. While they were returning via Beijing in 1704, the Qing ruler, the Kangxi Emperor, let them stay there for some years and later organized a 'khoshuu' for them in a place called Sertei, and made Ravjir the governor.

In 1716, the Kangxi Emperor sent him with his people to Hami, near the border of Qing China and Zunghar Khanate, for intelligence-gathering purposes against the Oirats. When Ravjir died his eldest son Denzen succeeded him. He was afraid of the Zunghar and wanted the Qing government to allow them to move away from the border. They were settled in Dalan Uul–Altan. When Denzen died in 1740, his son Lubsan Darjaa succeeded him and became Beil. Now[when?] Ejine Torghuts number some 5000[citation needed].

In 1753, they were settled on the banks of the Ejin River and the Ejin River Torghut 'khoshuu' was thus formed.[34]

^Owen Lattimore, The Desert Road to Turkestan. (For Lattimore, Euleuths are "the great western group of tribes which marks in all probability a primitive racial cleavage" (p. 101 in the ca. 1929 edition). Lattimore further (p. 139 refers to Samuel Couling of The Encyclopaedia Sinica (1917), according to whom the spelling "Eleuth" was due to French missionaries, representing the sound of something like Ölöt. Into Chinese, the same name was transcribed as 厄鲁特 (Pinyin: Elute; Mongolian: Olot).))

^M.Sanjdorj, History of the Mongolian People's Republic, Volume I, 1966